A group of Wrens outside one of the huts on the HMS Pembroke V site - an outstation of Bletchley Park during WW2

Historians are trying to track down women who worked at a top secret Ministry of Defence site to help unveil a plaque preserving their place in history.

The site in Eastcote , between Eastcote Road and Lime Grove, played an important role during the Second World War, known at that time as HMS Pembroke V.

It was an outstation to the now renowned but then ultra secret Bletchley Park, the first place of its kind to use early computer technology to intercept and decode German signals , and the setting of a new film, The Imitation Game, about pioneering mathematician Alan Turing , played by Benedict Cumberbatch, who helped to crack the Enigma code.

A Parade Inspection just inside the gates of HMS Pembroke V, at the end of Lime Grove, Eastcote

The code-breaking centre at Eastcote – which later became the Government Communications Headquarters (GCHQ) before the operation moved to Cheltenham – remained a secret until the 1970s.

It is now Pembroke Park Estate, a housing development which has commemorated the code-breaking history of the site in the names of its roads and buildings.

Susan Toms, honorary secretary of the local history society, said: “It was the largest outstation to Bletchley, with more than 800 Wrens working there, who operated 110 decoding bombes.[Electro-mechanical decoding machines to help decipher Enigma encrypted messages ].

“It is so important that we make some mark of the history because nobody at the time knew what was going on there and just how important the work was – a lot of people still do not know.

“There are no longer any physical traces of the site after the housing estate was built, so we wanted to install something visible that people can go and read and find out about this important piece of our local history,” she said.

Three Wrens completing cleaning chores at HMS Pembroke V

The society hopes to track down members of the Women’s Royal Naval Service (Wrens) who may have worked at the site during the war, or in the period after the end of the conflict, or who may have memories associated with the site, so that they can be invited to attend an unveiling ceremony on November 20.